HEXAVALENT CHROMIUM OBSERVATIONS ON SERVICED COMPONENTS OF OIL&GAS GAS TURBINES: FORMATION MECHANISM STUDY

Hexavalent chromium Cr(VI) is one of the oxidation states (+6) of chromium. It is a recognized toxin and carcinogen, which if ingested or inhaled may affect the respiratory system, kidneys, and liver. It can also cause dermatitis and severe irritation to the eyes. It is widely present in electroplating, anodizing and dye production industries, but has recently been identified as contaminant on serviced components of gas turbines. To this regard, there is the potential for Cr(VI) compounds to be present on gas turbine components serviced at high temperature, if calcium-containing insulating, anti-seize or sealing products are used. A systematic experimental campaign was carried out to investigate the mechanism and understand the influence of various factors on the formation of substances containing chromium in the hexavalent form. During the test campaign, anti-seize products, sealing products, insulating products but also environmental contaminants were tested on different bare materials in different service conditions.